1. Field of the Invention
This invention relates generally to gas turbine engines and, more particularly, to lubricant scavenge systems for such engines.
2. Description of the Prior Art
Lubricant scavenge systems, referred to hereinafter simply as oil scavenge systems, in gas turbine engines remove lubricant from a sump area within the engine adjacent components, typically bearings, which require constant lubrication during engine operation. Because it is often desirable to avoid submerging the lubricated component in lubricant, oil scavenge systems in aircraft propulsion gas turbine engines may include multiple scavenge pumps drawing lubricant from the sump through multiple pick-up locations in the sump so that scavenging is assured regardless of the attitude of the engine and aircraft. Multiple pumps and their associated connections and hardware, however, increase weight and complexity of the engine and also the cost. In addition, in multiple pump systems where the sump is inboard of the gas flow path, the flow lines to the scavenge pumps which traverse the gas flow path may be susceptible to coking of the residual oil therein when not flowing significant quantities of oil. Other oil scavenge systems in aircraft gas turbine engines assure adequate scavenging at all aircraft altitudes by pressurizing the sump to force the oil thru the scavenge pump lines. In these systems, special sump seals are required to maintain sump pressurization. An oil scavenge system according to this invention represents a new and improved alternative to these types of systems in that it does not rely upon sump pressurization nor multiple scavenge pumps and associated hardware to assure adequate sump scavenging at all attitudes and altitudes at which the engine may operate.